1. Field of the Invention
The present invention relates to a burring device, and more particularly to a burring device suitable for processing of tubular walls.
2. Description of the Related Art
Examples of burring devices for tubular surfaces include those which push a metal core ball out through a lower hole formed in the tube, thereby deforming outward the circumferential edge of the lower hole (Refer to Japanese Patent Application Laid-open No. S59-33036 (FIG. 2 and FIG. 3) and Japanese Patent Application Laid-open No. H8-197151 (FIG. 3 and FIG. 7) for example).
Incidentally, with the burring devices of Japanese Patent Application Laid-open No. S59-33036 (FIG. 2 and FIG. 3) and Japanese Patent Application Laid-open No. H8-197151 (FIG. 3 and FIG. 7), the circumferential edge of the lower hole is deformed by the ball by being pushed out through the lower hole from inside the tube to perform the burring process, but when the next burring process is to be performed, the ball must be returned to the original position, and considerable effort is needed to perform a continuous burring operation.